1. Field of the Invention
The present invention relates to a magnetic head apparatus, a magnetic reproducing method, and a magnetic reproducing apparatus in a linear tape system. More particularly, the present invention relates to a technology of reproducing a narrow recording track according to non-tracking mode in a linear tape system.
2. Description of Related Art
A conventional linear tape system uses a magnetic tape T whose recording track Tr has a track width Trw of 10 to 20 μm. A reproducing head Rh has a head width Rhw almost the same as that of the recording track Tr (see FIG. 7).
The tracking accuracy just needs to be one to several microns because the recording track Tr has the track width Trw of 10 to 20 μm.
If a fluctuation of, e.g., ±2 μm (off-track amount: ±TOFF) occurs with reference to the width (10 to 20 μm) of the recording track Tr, a signal reproduced from the reproducing head Rh is subject to degradation of 2/10 to 2/20. This is assumed to be a tolerance. Though FIG. 7 represents as if the reproducing head Rh moves up and down against the recording track Tr, the figure shows relative positions. Actually, the recording track Tr moves up and down while the magnetic tape moves.
A fluctuation amount for the magnetic tape T is equivalent to the off-track amount ±TOFF according to the relationship between the reproducing head Rh and the recording track Tr. The off-track amount ±TOFF indicates an amount of deviation in a width direction based on a state where the reproducing head Rh and the recording track Tr are centered on each other in the width direction. Even if an off-track state occurs, there is provided a limit value of the off-track amount ±TOFF for allowing the reproducing head Rh to reproduce a recorded signal. This off-track amount ±TOFF is referred to as an allowable off-track amount. The allowable off-track amount depends on performance of the reproducing head Rh and is therefore designed individually.